Originally Posted by RickEis

Very cool Dennis !!!

Can you post a schematic for us to work with ?

- I'm sure there is someone out there who could help with the graphic/characters

Rick

It's pretty much the basic schematic suggested in the MAX7456 datasheet. Ac-couling of video-signal, 75-ohm impedance on input and output, some pull-up resistors on LOS, H- and V-sync and I2C connections to a microcontroller. I don't have the schematic on this computer and would like to confirm the design before showing anything more specific.

I finally got my arduino compatible RC board made. I decided to add the GPS module. It's got the LM1881 and OSD interface components on the back. The blank boards just arrived today, so I've still got some assembly and testing to do.

Paul

Originally Posted by PMB-NZ

I finally got my arduino compatible RC board made. I decided to add the GPS module. It's got the LM1881 and OSD interface components on the back. The blank boards just arrived today, so I've still got some assembly and testing to do.

Paul

They look good Paul

Originally Posted by PMB-NZ

I finally got my arduino compatible RC board made. I decided to add the GPS module. It's got the LM1881 and OSD interface components on the back. The blank boards just arrived today, so I've still got some assembly and testing to do.

Paul

Year, looks good. You have quite a few headers available, are they used for servo-control etc?

Thanks.

The double row headers in the middle are the general Arduino cpu-i/o, power and the osd-video. The tripple row at the bottom ha 8 channels of servo out, one serial ppm in and main power in (7-15VDC). Near the cpu adre the ISP and FTDI headers.

I built a one-off prototype 3 or 4 months back that didn't have the GPS and eeprom. The paste stencil for this board should be here in a few days Then I can see if it all works.

The servo drive uses a 4017 counter and needs some code to handle the timer. The serial PPM in needs some code and a capture to read a series of channels. I hope it will be relatively low overhead.

I was thinking about making a small gyro-accelerometer board to plug into the ISP header to do stability control. It probably wouldn't do stability and OSD at the same time, but it's small enough that I can use two boards.

I'm still working on documenting it. I have a bad habit of buiding things and then doing the drawings later.

Paul

Originally Posted by PMB-NZ

I'm still working on documenting it. I have a bad habit of buiding things and then doing the drawings later.

Paul

Not documenting things, is that a bad habbit?
Well, I have a lot to learn

Sounds like an interesting project. I would recommend a controller for dedicated OSD and another one for processing data, controlling servos etc. will make things a lot easier.

Can I ask what GPS-module you have used?

Waiting for paste stencil? Just grap a soldering iron

Originally Posted by Dennis Frie

Not documenting things, is that a bad habbit?
Well, I have a lot to learn

Sounds like an interesting project. I would recommend a controller for dedicated OSD and another one for processing data, controlling servos etc. will make things a lot easier.

Can I ask what GPS-module you have used?

Waiting for paste stencil? Just grap a soldering iron

I've got a few project that are still just documented on scraps of paper
But I've been using a blog lately and finding it easier to create and update.

The GPS is UBlox module (NEO-6Q). I got some a while ago from the local rep and they were not too expensive. There is at least one footprint compatible module available. The antenna is off-board. I've been using a amplified antenna that looks like a GPS Mouse, DC up the coax for the amplifier. It's a bit heavier but works well.

I assembled the prototype with the soldering iron... that was a fun evening The cpu is only about 5x5 mm with 32 pins and the resistor packs are small.

Paul

And I see you added the eeprom for the uBlox!
Mine was driving me nuts with just the backup battery.

The eeprom isn't connected to the Ublox. I had a bit of board space left and threw in a 24LC512 footprint connected to the CPU. On the back of the eeprom area is mounting for a small super-cap. The eeprom was just for some data logging.

I also find that it takes ages to get a fix sometimes. Can be 2 or 3 minutes if it hasn't been used in a while. Altitude takes even longer to stabilize and needs 6+ satellites to be reasonably reliable.

Paul

I ended up soldering the pins to get a specific start mode and I do all the initialization using code.
But I get longer 3D fix times from a cold restart. Last time I timed it to be ~400s. (6 Minutes)

Originally Posted by PMB-NZ

The eeprom isn't connected to the Ublox. I had a bit of board space left and threw in a 24LC512 footprint connected to the CPU. On the back of the eeprom area is mounting for a small super-cap. The eeprom was just for some data logging.

I also find that it takes ages to get a fix sometimes. Can be 2 or 3 minutes if it hasn't been used in a while. Altitude takes even longer to stabilize and needs 6+ satellites to be reasonably reliable.

Paul

Please keep us updated when you get it assembled and tested

I have ordered a 1 Mb EEPROM to test - would be great to be able to log voltage, current, GPS-coordinates etc.

Just updated the PCB-design. Had to change the crystals in order to keep the same footprint and make space for I2C, PPM-input, voltage-regulator and some extra caps

Masterful!

Originally Posted by rimshotcopter

Masterful!

Thanks
It almost looks like there is plenty of space when you can't see the traces

Amidst these other PCB related posts, I'm just going to say that as of today mine is finally adequate to be sent for manufacture.

https://github.com/Legot/OSD-Board